Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/02—Stamping using rigid devices or tools
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
  • C21D9/48—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals deep-drawing sheets
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/18—Hardening; Quenching with or without subsequent tempering
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/26—Methods of annealing
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/26—Methods of annealing
  • C21D1/30—Stress-relieving
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D11/00—Process control or regulation for heat treatments
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D6/00—Heat treatment of ferrous alloys
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D7/00—Modifying the physical properties of iron or steel by deformation
  • C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
  • C21D7/10—Modifying the physical properties of iron or steel by deformation by cold working of the whole cross-section, e.g. of concrete reinforcing bars
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
  • C21D8/0236—Cold rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
  • C21D8/0405—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing of ferrous alloys
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
  • C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
  • C21D8/0494—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing involving a localised treatment
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/34—Methods of heating
  • C21D1/42—Induction heating
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/34—Methods of heating
  • C21D1/52—Methods of heating with flames
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/001—Austenite
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/002—Bainite
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/005—Ferrite
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/008—Martensite
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/009—Pearlite
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2221/00—Treating localised areas of an article
  • C21D2221/02—Edge parts
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2261/00—Machining or cutting being involved
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N2203/0014—Type of force applied
  • G01N2203/0025—Shearing
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N2203/0058—Kind of property studied
  • G01N2203/006—Crack, flaws, fracture or rupture
  • G01N2203/0062—Crack or flaws
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• the present invention relates to a method for manufacturing a steel sheet for cold pressing, and a method for manufacturing a pressed part.
• the present invention particularly relates to a technique suitable for a press part made of a high-strength steel plate.
• a high-strength steel sheet composed of a single-phase martensite has a very hard structure, a large amount of work hardening is introduced, and the toughness tends to decrease significantly. Formability is significantly reduced.
• the high-strength steel sheet composed of a composite structure mainly composed of martensite and ferrite is responsible for the strength in the hard martensite phase and the elongation in the soft ferrite phase.
• a high-strength steel sheet composed of a composite structure containing residual austenite is transformed into a hard martensite phase after deformation of the retained austenite phase during forming, which causes strain during deformation. It can be dispersed and very high elongation can be obtained.
• a high-strength steel sheet composed of a composite structure containing residual austenite transforms to the martensite phase, the stress concentration at the grain boundaries accompanying the volume change during the transformation from the austenite phase to the martensite phase.
• strain concentration to occur at the crystal grain boundaries due to the increase in hardness difference from the surrounding structure caused by the increase in hardness.
• the high-strength steel sheet composed of a composite structure containing retained austenite has low stretch flange formability.
• the stretch flange cracking concern part is the sheared surface
• the stainless steel transforms into martensite during shearing, the workability of the sheared end face decreases and the stretch flange formability deteriorates.
• Patent Document 1 As a technique for improving the workability of a high-strength steel sheet, for example, Patent Document
• This technology is a technology in which a steel sheet is heated to a predetermined temperature to soften it, and then the steel sheet is placed in a mold while maintaining that temperature, and forming and quenching are performed simultaneously. With this technology, since the steel sheet is soft during processing, cracking does not occur, and it is possible to obtain a hard product that has been hardened after processing.
• Patent Document 2 discloses a technique of locally softening the steel sheet to locally improve the formability by partially heating the steel sheet to a recrystallization temperature or higher (800 ° ⁇ or higher). .. ⁇ 0 2020/175486 3 (: 17 2020/007513 Prior art documents)
• Patent Document 1 Patent No. 5 9 0 2 9 3 9
• Patent Document 2 Japanese Patent Laid-Open No. 9-1 4 3 5 5 4
• Patent Document 1 requires heating the steel sheet to a predetermined temperature, and charging the steel sheet into the mold at that temperature. Therefore, in Patent Document 1, a furnace or a heating device similar thereto is provided in the manufacturing line, and further, a device for moving a high-temperature steel plate from the furnace into the mold is required, resulting in high cost. Further, in Patent Document 1, in addition to the time required for heating the steel sheet, since it is necessary to perform quenching in the mold, a holding time in the mold is required. Furthermore, in Patent Document 1, it is necessary to secure a time for cooling the mold after molding, which results in a large time cost.
• Patent Document 2 has a problem that the brittleness decreases due to recrystallization, so that the effect against elongation flange cracking is low.
• the present invention was devised to solve the above problems, and an object of the present invention is to improve stretch flange formability of a steel sheet without heating the material in the mold.
• the inventor has found that when heating and cooling the edges of a steel sheet, it is possible to improve stretch flange formability by appropriately setting the heating temperature range individually according to the material of the steel sheet. discovered. That is, it was found that the heat treatment according to the structure of the steel sheet is individually performed to improve the stretch flange formability of the pressed part. ⁇ 0 2020/175 486 4 ⁇ (: 170? 2020 /007513
• an aspect of the present invention is a method for manufacturing a cold-pressing steel sheet that is cold-pressed, wherein at least an end portion of the steel sheet is provided.
• the region in which stretch flange cracking is likely to occur when formed by cold press working Analysis step to be obtained and heating/cooling step of heating and cooling the part of the end of the steel sheet included in the above area obtained in the analysis step to a heating temperature range preset according to the structural structure of the steel sheet when have, when the main tissue as the steel sheet using a steel sheet consisting of martensite single phase, and set the heating temperature range to 5 0 0 ° ⁇ as 7 0 0 ° ⁇ following heating temperature range
• the steel sheet a steel sheet whose main structure is a composite structure of martensite and a ferrite,
• the gist is to set the above heating temperature range to a heating temperature range of not less than 200° and not more than 700°.
• Another aspect of the present invention is a method for producing a press part, which comprises subjecting a steel sheet to cold press work to produce a press part having a desired press part shape.
• a first step of press-forming the steel plate into an intermediate part and a second step of press-forming the intermediate part into a desired press part shape, further, before the first step,
• a shearing step is performed in which at least a part of the end of the steel plate is sheared, and the intermediate part is press-formed into the desired press part shape in the second step among the ends of the intermediate part.
• Stretch flange Deformation was performed in the analysis process of the end part of the intermediate part formed in the first process before the second analysis process and the analysis process to determine the region where cracking is likely to occur.
• a heating/cooling step of heating a portion included in the above region to a heating temperature range preset according to the structural structure of the steel sheet and cooling, and the main structure of the steel sheet is a martensite single phase.
• the heating temperature range is from 5,000 to 7,000 degrees and below, and as the steel sheet, the main structure is a steel sheet composed of a composite structure of martensite and ferrite, and the main structure is bainite single steel.
• the above heating temperature range is set to 40 set to 0 ° ⁇ as 7 0 0 ° ⁇ following heating temperature range, when using a Ru steel name from a composite structure containing retained austenite as the steel sheet, the heating temperature range 2 0 0 ° ⁇ as 7 0 The main point is to set the heating temperature range below 0 ° ⁇ .
• another aspect of the present invention is a method for manufacturing a pressed part, which comprises subjecting a steel sheet whose main structure is a martensite single phase to cold pressing to produce a pressed part having an intended pressed part shape. Then, the cold press working includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape.
• a shearing step of subjecting at least a part of the end of the intermediate part to a shearing step, and among the ends of the intermediate part after the shearing is performed, Before the second step and the analysis step to find the region where it is estimated that elongation flange cracks are likely to occur when the intermediate part is press-formed into the desired press part shape in step 2, Of the ends of the intermediate part that has been sheared, the part included in the above area determined in the above analysis step is heated to a temperature range preset according to the structural structure of the steel sheet and cooled.
• the above heating temperature range is not less than 500°C and not more than 700°C.
• the steel sheet mainly composed of a composite structure of martensite and ferrite, the steel sheet mainly composed of bainite single phase, and the steel sheet mainly composed of single phase ferrite.
• the heating temperature range above shall be 40 0 ° ⁇ or more and 70 0 ° ° or less set, when using the composite tissue or Ranaru steel containing residual austenite as the steel sheet, the heating temperature range 2 0 0 ° ⁇ as 7 0 0 ° ⁇ following ⁇ 0 2020/175486 6 6 (: 170? 2020 /007513
• the point is to set the heating temperature range.
• Another aspect of the present invention is a method for producing a cold-pressed steel sheet for cold pressing, wherein the steel sheet mainly has a martensite single-phase structure.
• the steel sheet mainly has a martensite single-phase structure.
• another aspect of the present invention is a method for manufacturing a pressed part, in which a steel plate whose main structure is a martensite single phase is cold-pressed to manufacture a pressed part having an intended pressed part shape. Then, the cold press working includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape. Prior to the first step, a shearing step is performed in which at least a part of the steel sheet is sheared, and among the end portions of the above intermediate part, the intermediate part is used in the second step.
• a part included in the above-mentioned region obtained in the above-mentioned analysis step is heated to a temperature range of ⁇ 500°° and ⁇ 700°°, and is cooled.
• Another aspect of the present invention is a method of manufacturing a press part, which comprises subjecting a steel sheet whose main structure is a martensite single phase to cold press to produce a press part having an intended press part shape. Then, the cold press working includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape. Before the second step, a shearing step of subjecting at least a part of the end of the intermediate part to a shearing step, and among the ends of the intermediate part after the shearing is performed, D of 2 ⁇ 0 2020/175 486 7 ⁇ (: 170? 2020 /007513
• the shearing process is performed before the analysis process and the second process, in which an area in which elongation flange cracking is likely to occur is obtained.
• the part included in the above-mentioned region obtained in the above-mentioned analysis step is heated to a temperature range of ⁇ 500°° and ⁇ 700°°, and cooled.
• the gist is to have a cooling step.
• another aspect of the present invention is a method for manufacturing a cold-pressed steel sheet for cold pressing, wherein the steel sheet has a main structure of martensite and ferrite.
• a shearing step of performing shearing on at least part of the edges of the steel sheet, and cold pressing of the edges of the steel sheet sheared in the shearing step.
• the main point is to have a heating/cooling step of heating and cooling in a temperature range of ⁇ 0 and ⁇ 7,000 ° .
• another embodiment of the present invention is a press for producing a press part having a desired press part shape by cold-pressing a steel plate whose main structure is a composite structure of martensite and ferrite.
• a method of manufacturing a component comprising, as the cold press working, a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired pressed part shape. Further, prior to the above-mentioned first step, a shearing step in which at least a part of the end of the steel sheet is sheared, and among the end parts of the intermediate part, the intermediate step in the second step is performed.
• a steel plate whose main structure is a composite structure of martensite and ferrite is cold-pressed to obtain a desired press part shape. ⁇ 0 2020/175 486 8 ⁇ (: 170? 2020 /007513
• a method of manufacturing a pressed part which comprises a first step of press-forming the steel sheet into an intermediate part and a step of forming the intermediate part into an intended pressed part shape as the cold-pressing. And a shearing step of applying shearing force to at least a part of the end of the intermediate part before the second step, and a step of performing the shearing process.
• the gist is to have a heating/cooling step of heating and cooling to a temperature range below.
• Another aspect of the present invention is a method for manufacturing a cold-pressed steel sheet for cold pressing, wherein the steel sheet is a steel sheet made of a composite fabric containing residual austenite.
• the steel sheet is a steel sheet made of a composite fabric containing residual austenite.
• the analysis process to find the region where stretch flange cracking is likely to occur, and the part of the end of the steel plate that is included in the region obtained in the analysis process above,
• the gist is to have a heating/cooling step of heating and cooling to a temperature range of ° ⁇ or less.
• Another aspect of the present invention is a method for producing a pressed part, which comprises subjecting a steel sheet having a composite structure containing residual austenite to cold pressing to produce a pressed part having an intended pressed part shape.
• the cold pressing includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape.
• a shearing step in which at least a part of the end of the steel sheet is sheared, and among the ends of the intermediate part, in the second step, the intermediate part is used as a target press.
• the first step before the second step and the analysis step to obtain the region where it is estimated that stretch flange cracks are likely to occur when press forming into the part shape ⁇ 0 2020/175 486 9 ⁇ (: 170? 2020 /007513
• the part included in the above area determined in the above analysis process is heated and cooled to a temperature range of 200 ° ⁇ or more and 700 ° ⁇ or less.
• the main point is to have.
• Another aspect of the present invention is a method for producing a pressed part, which comprises subjecting a steel sheet having a composite structure containing residual austenite to cold pressing to produce a pressed part having an intended pressed part shape.
• the cold pressing includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape.
• a shearing step is performed in which at least a part of the end of the intermediate part is subjected to a shearing process, and an end part of the intermediate part after the shearing is performed
• the shearing process is performed before the second process and the analysis process for obtaining the region where it is estimated that stretch flange cracks are likely to occur.
• the parts included in the above area determined in the above analysis process are heated and cooled to a temperature range of not less than 200° and not more than 700°.
• the gist is to have a process and.
• another aspect of the present invention is a method of manufacturing a press part, in which a steel plate having a bainite single phase as a main structure is cold-pressed to manufacture a press part having an intended press part shape.
• the cold pressing includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape.
• a shearing step is performed in which at least a part of the steel plate is sheared, and among the end parts of the intermediate part, the intermediate part is used in the second step.
• the main point is to have a heating/cooling step of heating and cooling in a temperature range of not less than 400° and not more than 700°.
• Another aspect of the present invention is a steel sheet whose main structure is bainite single phase, ⁇ 0 2020/175 486 10 ⁇ (: 170? 2020 /007513
• a method of manufacturing a press part for performing a cold press process to manufacture a press part having an intended press part shape comprising the first step of press forming the steel sheet into an intermediate part as the cold press process.
• the gist is to have a heating/cooling step of heating and cooling the part to a temperature range of 400°° or more and 700°° or less.
• another aspect of the present invention is a method for manufacturing a press part, in which a steel plate whose main structure is a ferrite single phase is cold-pressed to manufacture a press part having an intended press part shape.
• the cold pressing includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape.
• a shearing step is performed in which at least a part of the steel plate is sheared, and among the end parts of the intermediate part, the intermediate part is used in the second step.
• the main point is to have a heating/cooling step of heating and cooling in a temperature range of not less than 400° and not more than 700°.
• another aspect of the present invention is a method for manufacturing a press part, in which a steel plate whose main structure is a ferrite single phase is cold-pressed to manufacture a press part having an intended press part shape.
• the cold pressing includes a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired press part shape. , Before the second step above, ⁇ 0 2020/175 486 1 1 ⁇ (: 170? 2020 /007513
• the heating/cooling step of heating and cooling the part included in the above-mentioned area obtained in the above-mentioned analysis step to a temperature range of not less than 400° and not more than 700° is summarized. To do.
• another aspect of the present invention is a press for producing a press part having a desired press part shape by cold-pressing a steel plate whose main structure is a composite structure of ferrite and perlite.
• a method of manufacturing a component comprising, as the cold press working, a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired pressed part shape.
• a shearing step of shearing at least a part of the end of the steel sheet, and in the second step of the end of the intermediate part When the intermediate part is press-formed into the desired shape of the press part, the analysis process to find the area where stretch flange cracking is likely to occur, and the first process before the second process A heating/cooling step of heating and cooling a part of the end of the intermediate part included in the above-mentioned area obtained in the above-mentioned analysis step to a temperature range of not less than 400° and not more than 700°.
• the gist is to have.
• Another aspect of the present invention is a press for manufacturing a press part having a desired press part shape by cold-pressing a steel plate whose main structure is a composite structure of ferrite and perlite.
• a method of manufacturing a component comprising, as the cold press working, a first step of press-forming the steel sheet into an intermediate part, and a second step of press-forming the intermediate part into a desired pressed part shape. Further, before the second step, a shearing step of subjecting at least a part of the end of the intermediate part to a shearing step, and an end of the intermediate part after the shearing is performed.
• an analysis process to determine the region where stretch flange cracking is likely to occur when the intermediate part is press-formed into the desired press part shape in the second step ⁇ 0 2020/175 486 12 ⁇ (: 170? 2020 /007513
• a portion of the end portion of the intermediate part that has been subjected to the shearing process and included in the area obtained in the analysis step is set to 400°° or more and 70 ° or more. It is necessary to have a heating/cooling step of heating and cooling to a temperature range of ° ⁇ or less.
• the stretch flange formability of the steel sheet can be improved by individually performing the heat treatment according to the material (structural structure) of the steel sheet.
• a high-strength steel sheet whose main structure is a martensite single phase for example, a high-strength steel sheet whose main structure is a composite structure of martensite and a ferrite, and residual austenite High-strength steel plate composed of a composite structure containing, a high-strength steel plate mainly composed of bainite single phase, a high-strength steel plate mainly composed of ferrite single phase (precipitation-strengthened steel), or a main structure composed of ferrite.
• FIG. 1 is a diagram showing a process of manufacturing a pressed part according to a first embodiment of the present invention.
• FIG. 2 is a diagram illustrating a heating/cooling step according to the first embodiment of the present invention.
• FIG. 3 is a diagram showing an example of a heating method.
• FIG. 4 is a diagram showing an example of a heating method.
• FIG. 5 is a diagram showing an example of a heating method.
• FIG. 6 is a diagram showing an example of a heating method.
• Fig. 7 is a diagram showing an example of an analysis region (a region in which stretch flange cracking is likely to occur) according to the first embodiment of the present invention.
• FIG. 8 is a diagram showing a processing example of a heating/cooling step and a pressing step according to the first embodiment of the present invention. ⁇ 0 2020/175 486 13 ⁇ (: 170? 2020 /007513
• FIG. 9 is a diagram showing a processing block of a method for manufacturing a pressed part according to the second embodiment of the present invention.
• FIG. 10 is a diagram illustrating a process example of a method for manufacturing a pressed part according to the second embodiment of the present invention.
• FIG. 11 is a diagram showing a processing block of a method for manufacturing a pressed part according to the third embodiment of the present invention.
• FIG. 12 is a diagram illustrating a process example of a method for manufacturing a pressed part according to the second embodiment of the present invention.
• Fig. 13 is a diagram illustrating an example of a region in which stretch flange cracking occurs.
• ( 3 ) shows a steel plate (blank material), and
• ( ⁇ ) shows a pressed part after press forming.
• FIG. 14 is a view showing a test piece.
• FIG. 15 is a diagram for explaining the outline of the hole expanding test.
• Fig. 16 is a diagram showing the relationship between the heating temperature in the heating/cooling step and the hole expandability improvement rate in the case of a steel sheet whose main structure is a martensite single phase.
• Fig. 17 is a diagram showing the relationship between the heating temperature in the heating/cooling step and the hole expandability improvement rate in the case of a steel sheet whose main structure is a composite structure of martensite and ferrite.
• Fig. 18 is a diagram showing the relationship between the heating temperature in the heating/cooling process and the hole expandability improvement rate in the case of a steel sheet composed of a composite structure containing retained austenite.
• Fig. 19 is a diagram showing the relationship between the heating temperature in the heating/cooling step and the hole expandability improvement rate in the case of a steel sheet whose main structure is a bainite single phase.
• Fig. 20 is a diagram showing the relationship between the heating temperature in the heating/cooling step and the hole expandability improvement rate in the case of a steel sheet whose main structure is a single-phase ferrite.
• Fig. 21 is a diagram showing the relationship between the heating temperature in the heating/cooling step and the hole expandability improvement rate in the case of a steel sheet whose main structure is a composite structure of ferrite and perlite.
• the method for manufacturing a pressed part in the present embodiment includes a steel plate manufacturing step 1 and a press working step 2. As shown in Fig. 2, in the steel plate manufacturing process 1, the shearing process 1 and the heating/cooling process 1 are carried out in this order.
• the method for manufacturing a pressed part according to the present embodiment has a stretch flange crack region estimation process 3 which constitutes an analysis step.
• the tensile strength of the steel sheet 4 4_Rei [ ⁇ 9 3 or more, more is particularly effective in the case of a steel sheet consisting of 9 8 0 1 ⁇ / 1? 3 or more high-strength steel sheets.
• the present embodiment can be applied even to a steel plate having a tensile strength of less than 440 IV! 3 .
• a steel plate consisting of one plate formed by rolling or the like is trimmed into a preset blank material shape, or an opening is formed by shearing such as burring processing to form the desired shape. This is the process of obtaining a single steel plate (blank material).
• the [single _ of the steel sheet] means that instead of the set blank material obtained by bonding a plurality of plate by welding a steel plate made of the same metal material.
• the shearing part may be only a part of the steel plate.
• another shearing treatment for shaping the end face may be provided.
• the stretch flange crack region estimation process 3 is a stretch flange cracking process when the single steel sheet that was sheared in the shearing process 1 was press-formed in the press working process 2. ⁇ 0 2020/175 486 15 ⁇ (: 170? 2020 /007513
• the steel plate condition for obtaining the analysis region is the steel plate that has not been subjected to the heating/cooling step 1 process.
• stretch flange cracking area may be carried out by using a computer based on the conditions of press forming in the press working step 2 and by carrying out an analysis by means of 808 analysis. It may be specified by actual press.
• the curved portion, the parling portion, and the like in a plan view are stretch flange crack regions. Therefore, in a region where stretch flange forming is performed, a flange portion having a radius of curvature of a predetermined value or more by press working may be simply obtained as a stretch flange crack region (analysis region).
• the heating/cooling process No. 1 is a pre-treatment before pressing the single steel sheet after the shearing process 1 including elongation flange forming.
• heat treatment 1 process 3 and cooling process 1 process 13 are performed in this order.
• Heat treatment 1 At 3 the edge of the steel sheet is heated.
• the portion to be heated heats the steel plate end face by heating at least the steel plate end face of the steel plate end face and its vicinity.
• the heating of the steel plate end portion as described above, only the end face of the steel plate may be heated. However, since it is difficult to heat only the end face, it is preferable to heat the region near the end face of the steel plate end face and its vicinity with a laser that can be locally heated or induction heating. It is preferable to set. By heating the steel plate end surface, the steel plate end portion is heated.
• FIG. 3 shows an example of laser heating, in which the laser oscillator 20 is moved along the end face 10 3 to heat the end of the steel sheet.
• Figures 4 and 5 show induction ⁇ 0 2020/175 486 16 ⁇ (: 170? 2020 /007513
• induction heating coil 21 performs induction heating from the end face 103 side or both the front and back surfaces near end face 103 is illustrated.
• Figure 6 shows an example of heating by direct heating with the burner _ 22.
• Heating method laser heating, induction heating may be other than direct heating by Bas _ Na _ like, may be employed any heating means.
• the heating rate may be any rate from the viewpoint of improving stretch flange formability, but when heating is performed in the production process, from the viewpoint of mass productivity, 1 ⁇ or more is desirable. This does not apply if mass productivity is not a concern.
• the heating rate at the time of heating is preferably rapid heating.
• the holding time is preferably 5 minutes or less. More preferably, the retention time is within 1 minute.
• the blank material shape is rectangular and the shear end surface is shown as a straight line.
• the blank material may have any shape, and the shear end surface 103 is not limited to a straight line, and may have any shape such as a curved line or a combination of curved lines and straight lines.
• Heating range from the end face position of steel plate 10 on the surface of a single steel plate! -[01 111] is, for example, within the range of formula (1). That is, this heating range! -[01 111]
• the following areas shall be the end face that constitutes the end part and its vicinity.
• the heating range 1_[ is preferably as close to the end face as possible, and more preferably within the range of the following formula (2). ⁇ 0 2020/175486 17 17 (: 170? 2020 /007513
• the target heating temperature of the heated portion during heating is the target heating temperature of the heated portion during heating
• the steel sheet used in this embodiment is a steel sheet whose main structure is martensite single phase will be described.
• the steel sheet whose main structure is composed of martensite single phase is, for example, a steel sheet in which 95% by volume or more, preferably 98% by volume or more of the structure is martensite.
• the target heating temperature is [° ⁇ ] within the range of 500°° to 700°°.
• the steel sheet to be pressed is a steel sheet whose main structure is a martensite single phase
• Stretch flange formability is improved.
• the vicinity of the sheared end face of the steel sheet that has been subjected to shearing is subjected to strong processing that stretches the structure in the shearing direction, and there is a concern that shear hardening causes hardening and elongation and flangeability.
• the above heating causes tempering of the martensite and release of strain.
• the tempering of the martensite softens the edges of the steel sheet and the release of strain causes work hardening and recovery of toughness, improving stretch flange formability.
• Heating temperature in order to obtain the above effects, 5 0 0 ° ⁇ As as described above, preferably a 6 0 0 ° ⁇ As.
• the upper limit temperature of heating shall be 70°C or lower, which is the temperature range where recrystallization is not expected to occur.
• the heating range from the end face position of the steel sheet 10!-[] is the heating temperature [° ⁇ ⁇ 0 2020/175 486 18 (: 17 2020/007513
• the heating range !- from the end face position of the steel plate 10 is set, for example, in a direction along the steel plate surface and a direction orthogonal to the extending direction of the end face.
• the range satisfies the following expression (4).
• the reached temperature of heating is a region of 500 ° C or higher.
• the heating range! If-is less than the lower limit value of the expression (3), it may not be possible to sufficiently heat the end portion of the steel sheet and the effect of the present invention cannot be sufficiently obtained. Also, the heating range! - The upper limit is not set from the viewpoint of improving stretch flangeability, but if the heating range is too wide, there is a concern that the softening of the martensite of the base material may cause deterioration of part performance, spot weldability, etc. , It is desirable that the range is less than or equal to the upper limit of equation (3).
• the steel plate used in the present embodiment will be described as a steel plate whose main structure is a composite structure of martensite and ferrite (hereinafter, also referred to as a first composite structure).
• a steel sheet whose main structure is a composite structure of martensite and ferrite means, for example, that the martensite phase is less than 95% by volume of the structure and the non-ferrite phase containing residual austenite phase is less than 3% by volume. Yes, and the balance is a steel plate consisting of a ferrite phase.
• the target heating temperature [° ⁇ ] of the heated part during heating shall be in the range of 400° o or more and 700° o or less.
• the steel sheet to be pressed is a steel sheet whose main structure is a composite structure of martensite and ferrite
• the end face of the steel plate is By heating, the stretch flange formability is improved.
• the vicinity of the sheared end face of the steel sheet that has been subjected to shearing is subjected to strong processing that stretches the structure in the shearing direction, and work hardening occurs due to shearing, and there is concern that stretch flangeability may deteriorate.
• the above heating causes tempering of the martensite and release of the strain.
• the heating temperature Ding in order to obtain the above effect, as described above 4 0 0 ° ⁇ As, preferably 5 0 0 ° ⁇ As, more preferably a 6 0 0 ° ⁇ As.
• the upper limit temperature of heating shall be 70°C or lower, which is the temperature range where recrystallization is not expected to occur.
• the heating range from the end face position of the steel plate 10! -[01 111] may be set according to the heating temperature [°0], for example, set within the range of the following formula (5).
• Heating range from the end face position of steel plate 10! -[111 111] is set, for example, in the direction along the steel plate surface and in the direction orthogonal to the extending direction of the end face.
• Heating range! -[] is preferably a range that satisfies the following expression (6). ⁇ 0 2020/175 486 20 ((17 2020/007513
• the ultimate temperature of heating is 400 ° C or higher.
• the heating range! - When [111 111] is less than the lower limit value of the expression (5), it may not be possible to sufficiently heat the end portion of the steel sheet, and the effect of the present invention may not be sufficiently obtained. Also, the heating range! - The upper limit of is not set in particular from the viewpoint of improving stretch flangeability, but if the heating range is too wide, the strength of the base material will decrease due to heating, which may cause deterioration of part performance, spot weldability, etc. Therefore, it is desirable to keep the range below the upper limit of equation (5).
• the steel sheet used in this embodiment is a steel sheet having a composite structure containing retained austenite (hereinafter also referred to as a second composite structure).
• a steel sheet composed of a composite structure containing residual austenite is, for example,
• residual austenite means, for example, the residual austenite is 3% by volume or more, preferably 4% by volume or more of the whole tissue.
• the composite structure other than retained austenite is mainly composed of the ferrite phase, bainite phase, and martensite phase.
• the target heating temperature [° ⁇ ] of the heated part during heating is within the range of 200 ° ⁇ to 70 00 ° ⁇ .
• the heating temperature is [200 ° ] or more, preferably 500°° or more, more preferably 600°° or more, as described above.
• the upper limit temperature of heating shall be 700°C or lower, which is the temperature range where recrystallization is not expected.
• the heating range from the end face position of the steel plate 10!-[ ⁇ !] is the heating temperature [ ° 0 ], for example, it may be set within the range of the following formula (7).
• the heating range from the end face position of the steel plate 10!-[ 01 111] is set, for example, in the direction along the steel plate surface and in the direction orthogonal to the extending direction of the end face.
• Heating range! -[ ⁇ !] is the range that satisfies the following expression (8).
• the heated region is heated, it is assumed that the ultimate temperature of heating is 200 ° C. or higher.
• the heating range! If the upper limit of [ ⁇ !] exceeds the upper limit of equation (7), the ductility of the base material may decrease due to the disappearance of residual austenite of the base material, and the stretch flangeability and press formability may decrease. Therefore, the effect of the present invention may not be sufficiently obtained.
• the steel sheet used in the present embodiment is a steel sheet whose main structure is bainite single phase will be described.
• a steel sheet having a bainite single-phase main structure is, for example, a steel sheet having a bainite content of 95% by volume or more, preferably 98% by volume or more of the structure.
• the target heating temperature [° ⁇ ] shall be within the range of 400° o or more and 700° o or less. By setting the heating temperature to 400° or more and 700° or less, it is possible to improve the flange formability in the case of a steel plate whose main structure is bainite single phase. See example).
• the steel sheet to be pressed is a steel sheet whose main structure is bainite single phase
• Stretch flange formability is improved.
• the vicinity of the sheared end face of the steel sheet that has been subjected to shearing is subjected to strong processing that stretches the structure in the shearing direction, and work hardening occurs due to shearing and there is concern that the stretch flange formability will deteriorate.
• the above heating causes tempering of the bainite and release of strain.
• the tempering of the bainite softens the edges of the steel sheet, and the release of strain causes work hardening and recovery of toughness, improving stretch flange formability.
• the heating temperature Ding [° ⁇ ] in order to obtain the above effect, as described above 4 0 0 ° ⁇ As, preferably 5 0 0 ° ⁇ As, more preferably a 6 0 0 ° ⁇ As.
• the upper limit temperature of heating shall be 70°C or lower, which is the temperature range where recrystallization is not expected to occur.
• the heating range from the end face position of the steel sheet 10!-[] depends on the heating temperature, [° ⁇ ]. It may be set such that it falls within the range of formula (9) below.
• the heating range !- from the end face position of 10 is set, for example, in the direction along the steel plate surface and in the direction orthogonal to the extending direction of the end face.
• Heating range! -[ ⁇ !] is preferably in the range that satisfies the following expression (10).
• the reached temperature of heating is a region of 400°C or higher.
• the steel sheet used in this embodiment is a steel sheet whose main structure is a single ferrite phase will be described.
• the steel sheet whose main structure is composed of a ferrite single phase is, for example, a steel plate in which 95% by volume or more, preferably 98% by volume or more of the structure is a ferrite.
• the target heating temperature [° ⁇ ] shall be in the range of 400° o or more and 700° o or less.
• the heating temperature [° ⁇ ] it is possible to improve the flange formability in the case of a steel sheet whose main structure is composed of a ferrite single phase.
• the steel sheet to be pressed is a steel sheet whose main structure is a ferrite single phase
• Stretch flange formability is improved.
• the vicinity of the sheared end face of the steel sheet that has been subjected to shearing is subjected to strong processing that stretches the structure in the shearing direction, and work hardening occurs due to shearing and there is concern that the stretch flange formability will deteriorate.
• the above heating causes tempering of the ferrite and release of strain.
• the tempering of the ferrite softens the edges of the steel sheet, and the release of strain causes work hardening and recovery of toughness, improving stretch flange formability.
• the heating temperature Ding [° ⁇ ] in order to obtain the above effect, as described above 4 0 0 ° ⁇ As, preferably 5 0 0 ° ⁇ As, more preferably a 6 0 0 ° ⁇ As.
• the upper limit temperature of heating shall be 70°C or lower, which is the temperature range where recrystallization is not expected to occur.
• the heating range from the end face position of the steel sheet 10 is !-[] depending on the heating temperature [° ⁇ ]. It may be set such that it falls within the range of the following formula (11).
• the heating range from the end face position of the steel plate 10!-[] is set, for example, in the direction along the steel plate surface and in the direction orthogonal to the extending direction of the end face.
• Heating range! -[] is preferably a range that satisfies the following expression (12).
• the reached temperature of heating is a region of 400° C. or higher.
• the heating range! The upper limit of is not set in particular from the viewpoint of improving stretch flangeability, but if the heating range is set too wide, there is a concern that the performance of the base material may soften and the performance of parts and spot weldability may deteriorate. Therefore, it is desirable that the range is less than or equal to the upper limit of equation (1 1).
• the steel plate used in the present embodiment has a main microstructure of a composite structure of ferrite and perlite (hereinafter, referred to as The steel sheet consisting of 3) is also described.
• a steel sheet whose main structure is a composite structure of ferrite and perlite means, for example, that the sum of the phase fractions of the ferrite phase and the perlite phase is 97% or more and the phase fraction of the perlite phase is 5% or more. It is a steel plate made of steel with a structure of at least %.
• the target heating temperature [° ⁇ ] of the heated part during heating is at least 400°° and at least 70° ⁇ Within the range below.
• the end surface of the steel plate is set to the above-mentioned appropriate temperature range.
• the stretch flange formability is improved.
• the vicinity of the sheared end face of the steel sheet that has been subjected to shearing is subjected to strong processing that stretches the structure in the shearing direction, and there is a concern that work hardening will occur due to shearing and the stretchability of the flange will deteriorate.
• the above heating causes tempering of the parlite and release of strain.
• the heating temperature Ding [° ⁇ ] in order to obtain the above effect, as described above 4 0 0 ° ⁇ As, preferably 5 0 0 ° ⁇ As, ⁇ 02020/175486 26 ⁇ (: 17 2020/007513
• the upper limit temperature of heating shall be 700° ⁇ or lower, which is the temperature range estimated that recrystallization does not occur.
• the heating range from the end face position of the steel sheet 10!- [01111] is the heating temperature
• the value may be set according to the value of [°], for example, set within the range of the following formula (13).
• the heating range from the end face position of the steel plate 10!- [01111] is set, for example, in the direction along the steel plate surface and in the direction orthogonal to the extending direction of the end face.
• Heating range! -[] is preferably a range that satisfies the following expression (14).
• the ultimate temperature of the heating is 400 ° C. or higher.
• the heating range! If-is less than the lower limit value of the expression (13), it may not be possible to sufficiently heat the end portion of the steel sheet and the effect of the present invention cannot be sufficiently obtained. Also, the heating range! The upper limit of-is not set in particular from the viewpoint of improving stretch flangeability, but the heating range! - If the value is taken too wide, the material strength of the base material will decrease due to heating, which may reduce the performance of parts, spot weldability, etc. Therefore, it is desirable to keep the range below the upper limit of equation (1 3). ..
• Cooling treatment 1 The cooling process is performed by cooling at least the heated end of the steel sheet heated in heating treatment 1 3). ⁇ 0 2020/175 486 27 ⁇ (: 170? 2020 /007513
• the cooling process 1 to 13 after the heat treatment may be any of rapid cooling such as water cooling, air cooling, and slow cooling.
• the air cooling may be natural air cooling or air cooling by blowing air from a nozzle.
• the cooling rate may be adjusted by adjusting the output during laser heating or induction heating.
• Cooling treatment 1 Cooling by means of a groove is, for example, that the heated steel plate end surface is less than the lower limit of the target heating temperature [° ⁇ ] set individually according to the material (structure) of the steel plate, preferably 10 0 ° ⁇ hereinafter cooling as more preferably a 5 0 ° ⁇ below.
• the steel sheet for cold pressing in this embodiment is manufactured.
• the steel plate whose end surface is heated and cooled is subjected to cold press working including stretch flange forming to obtain a pressed part with the desired shape.
• Cold pressing is a one-step or two-step or more press forming process to form a steel sheet into a pressed part with the desired shape.
• the cold press working in the present specification refers to press forming without heating the steel sheet during the press working, and for example, the temperature of the steel sheet is set to the above-mentioned target set individually according to the material of the steel sheet.
• the press working is performed at a temperature lower than the lower limit of the heating temperature ([° ⁇ ]), preferably 100° C. or less, more preferably 50° C. or less.
• the stamped part with the desired shape manufactured in stamping process 2 does not have to be the final molded product (final product shape).
• the analysis area X which has the possibility of flange cracking corresponding to, is heated at the above heating temperature and then cooled.
• the steel plate 10 that has been subjected to such a treatment is press-formed into a target press part 11 having a target part shape by cold pressing as shown in Fig. 8 (slung).
• Fig. 13 (a) the blank material 10 using the steel plate having each of the above-mentioned microstructures is simply deformed by press forming to stretch the flange (Fig. 13 ( I tried pressing into a pressed part 11 as shown in 13).
• stretch flange cracking occurred at the portion indicated by reference numeral 8 in Fig. 13 (slung).
• the stretch flange formability depends on the cutting method of the material end portion subjected to the stretch flange deformation.
• a steel sheet is cut by, for example, shearing, it is more damaged than the end surface produced by machining, resulting in a non-uniform end surface state, so there is concern that the elongation flange formability will deteriorate.
• the stretch flange formability changes depending on the clearance.
• the steel plate used for press working is subjected to shearing at least in the stretch flange crack risk region.
• the end surface of the plate, which is prone to crack initiation, is heated to an appropriate temperature according to the material and cooled, and the steel plate subjected to this treatment is press-formed.
• the heat treatment 1 to 3 for softening the material should be performed with the end surface of the steel sheet and at least the end surface in the vicinity of the end surface as the target, followed by the cooling treatment 1 and 3). ⁇ 0 2020/175 486 29 ⁇ (: 170? 2020 /007513
• the target of the analysis process and the target of the heating/cooling process of the first embodiment is the intermediate part 40 formed by the intermediate press work of the press work in the press work process 2. Is different from the first embodiment (see FIG. 9).
• this embodiment is the same as the first embodiment.
• the method for manufacturing a pressed part according to the present embodiment is a method for manufacturing a pressed part in which a steel plate is cold-pressed to manufacture a pressed part having an intended pressed part shape.
• the method for manufacturing a pressed part of the present embodiment includes, as a cold press working step 2, a first step 28 for press forming a steel sheet into an intermediate part 40 and an intermediate part 40.
• this embodiment includes a shearing step 50, an analyzing step 51, and a heating/cooling step 52, as shown in FIG.
• a shearing process is performed on at least a part of the edge of the steel sheet 10.
• a steel sheet made of one sheet formed by rolling or the like is trimmed into a preset blank material shape, or an opening is formed by shearing such as parling. This is a process of obtaining a single steel plate (blank material) having a desired shape.
• the shearing part may be only a part of the steel plate.
• another shearing process for shaping the end face may be provided.
• the analysis process 51 is the intermediate part 40 in the second process 2 of the end parts of the intermediate part 40. ⁇ 0 2020/175 486 30 ⁇ (: 170? 2020 /007513
• analysis step 51 the process of analyzing the position of the stretch flange crack region (analysis region) is executed.
• stretch flange crack region a single steel sheet that had been sheared in the shearing process 50 was press-formed into the intermediate part 40 in the first process 28, and then the intermediate part 4 in the second process 2 This is an area where stretch flange cracking is likely to occur when 0 is press-formed into the target press part 11.
• the conditions for the steel sheet are those that have not been subjected to the heating/cooling process 1.
• the stretch flange crack area is a stretch flange crack risk area.
• Such a stretch flange crack region may be specified by studying it with a computer using a 0 analysis based on the conditions of press forming in the press working step 2. You may specify with a press.
• the curved portion and the burring portion in a plan view are stretch flange crack regions. Therefore, in a region where stretch flange forming is performed, a flange portion having a radius of curvature larger than a predetermined value by press working may be simply obtained as a stretch flange crack region (analysis region).
• the processing of this analysis step 51 is not particularly limited as long as it is before the heating/cooling step 52.
• the heating/cooling step 52 is included in the analysis area obtained in the analysis step 51 among the ends of the intermediate part 40 molded in the first step 28 before the second step 2
• the end portion of the intermediate component 40 is heated to a target heating temperature range individually set according to the structural structure of the target steel sheet, and then cooled.
• the individually set target heating temperature range is set to a temperature range of not less than 500°C and not more than 700°C. ..
• the main organization is ⁇ 0 2020/175 486 31 ⁇ (: 170? 2020 /007513
• a steel sheet having a composite structure In the case of a steel sheet having a composite structure, it is set in the temperature range of 400° o or more and 700° o or less.
• the temperature range is set to not less than 200° and not more than 700°.
• the intermediate part 40 made of a single steel plate formed in the first step 28 is pressed by the second step 2 including the extension flange forming in the second step. This is a pretreatment before applying.
• the heating/cooling step 52 is performed in the same manner as the heating/cooling step 1 of the first embodiment. That is, in the heating/cooling step 52, the heating/cooling step 1 of the first embodiment is carried out in the order of the heating treatment and the cooling treatment under the same conditions as the heating treatment 1 3 and cooling treatment 1 1 ..
• the description of the heating and cooling process will be omitted because it is the same as the process and conditions of the heating and cooling step 1 of the first embodiment except that the part to be heated and cooled is the end of the intermediate component 40. To do.
• the intermediate part 40 is made into the target part shape in the second step 2 as shown in FIG. 10 (3) for the steel plate sheared in advance in the analysis step 51.
• the crack estimation region 3 in which the stretch flange crack is estimated to occur at the end of the pressed part 11 is obtained by computer analysis or the like.
• the analysis area corresponding to the crack estimation area, in which stretch flange cracking in the intermediate part 10 is estimated to occur is obtained (see Fig. 10 ( ⁇ 0)).
• the steel plate 10 shear-processed as shown in Fig. 10 (distance) is formed into the intermediate component 40 in the first step 28 (Fig. 10 ( ⁇ )). ..
• the above-mentioned crack estimation area in the press part at the end of the intermediate part 40 The analysis area X at the end corresponding to ⁇ is heated at the above heating temperature and then cooled.
• the second process 2 ⁇ 0 2020/175 486 32 ⁇ (: 170? 2020 /007513
• the present embodiment has the same effects as the effects of the first embodiment.
• this embodiment also has the following effects.
• the stretch flange formability at the end of the press part after each press working also changes due to each press working, and The possibility of cracking in the final pressed part 11 may change depending on the processing conditions and other factors.
• the cold press process is a multi-stage press forming process
• the crack estimation area By performing heating/cooling processing on the analysis area, which is the end position of the intermediate part 40 corresponding to ⁇ , the second part 2 of the press part 11 of the desired part shape after Stretch flange Improves the crack suppression effect.
• the first step 28 and the second step 2 may each be composed of a plurality of press steps.
• computer analysis etc. is used to find the press work that is presumed to have a high risk of stretch flange cracking in the press work, and the press work before the press work in that press work is set to the above-mentioned intermediate part 40. Is also good.
• shearing in the first step 2 The heating/cooling treatment as described above may also be performed on the end portion corresponding to the analysis region at the end of the subsequent steel sheet 10.
• the press working process 2 includes three or more press working processes
• the press processes in the middle except the final press process are regarded as the first process, and the process of the second embodiment is performed. You may do each.
• the target of the shearing process and the heating/cooling process of the first embodiment is the intermediate part 40 formed by the intermediate press working of the press working in the press working process 2.
• this embodiment is the same as the first embodiment (see FIG. 11).
• the method of manufacturing a pressed part according to the present embodiment is a method of manufacturing a pressed part in which a steel plate is subjected to cold pressing to manufacture a pressed part having a desired pressed part shape.
• the manufacturing method of the pressed part of the present embodiment includes, as a cold press working step 2, a first step 28 of press forming a steel sheet into an intermediate part 40 and an intermediate part 4 A second step 2 for press forming 0 into a press part 1 1 having a target press part shape.
• this embodiment includes a shearing step 50, an analyzing step 51, and a heating/cooling step 52, as shown in FIG.
• a shearing process is performed on at least a part of the end of the intermediate part after the first step 28.
• the steel plate in the first step 2 may also be subjected to a separate shearing treatment.
• the process of analyzing the position of the stretch flange crack region is executed.
• a single steel plate is press-formed into the intermediate part 40 in the first step 28, and after shearing, the intermediate part 40 is targeted in the second step 2 This is an area in which stretch flange cracking is likely to occur when press forming is performed on the press part 11.
• the condition for a single steel plate is a steel plate that has not been subjected to the heating/cooling process 1 process. Further, other shearing treatment may be applied to the single steel plate before the first step 28.
• ⁇ 0 2020/175 486 34 ⁇ (: 170? 2020 /007513
• the lunge crack area is a stretch flange crack risk area.
• the identification of such a stretch flange crack region may be specified by studying it with a computer and performing an Omi analysis based on the press forming conditions in the press working step 2. You may specify.
• the curved portion and the burring portion in a plan view are stretch flange crack regions. Therefore, in a region where stretch flange forming is performed, a flange portion having a radius of curvature larger than a predetermined value by press working may be simply obtained as a stretch flange crack region (analysis region).
• the processing of this analysis step 51 is not particularly limited as long as it is before the heating/cooling step 52.
• the end part of the intermediate part 40 included in the analysis region obtained in the analysis step 51 is The target heating temperature range set individually according to the structure of the target steel sheet is heated and cooled.
• the individually set target heating temperature range is set to a temperature range of not less than 500° and not more than 700°.
• a steel sheet whose main structure is a composite structure of martensite and ferrite
• a steel plate whose main structure is bainite single phase
• a steel plate whose main structure is single phase ferrite
• it is set in the temperature range of 400°C or more and 700°C or less.
• the temperature range is set to not less than 200° and not more than 700°.
• the heating/cooling step 52 is the second step 2 including the stretch flange forming after the shearing treatment for the intermediate part 40 made of a single steel plate formed in the first step 28. This is a pretreatment before the press working in.
• the heating/cooling process 52 is the same as the heating/cooling process 1 of the first embodiment. ⁇ 0 2020/175 486 35 ⁇ (: 170? 2020 /007513
• the heating/cooling step 1 of the first embodiment is carried out in the order of the heating treatment and the cooling treatment under the same conditions as the heating treatment 1 3 and cooling treatment 1 1 ..
• the description of the heating and cooling process is omitted because it is the same as the process and conditions of the heating and cooling process No. 1 of the first embodiment except that the part to be heated and cooled is the end of the intermediate part 40. To do.
• the intermediate part 40 is cold-processed into the desired press part 11 having the desired part shape in the second step 2 in advance.
• Estimated crack area where stretch flange cracks are expected to occur in the target press part 11 when pressed. Is obtained by computer analysis.
• the analysis step 51 is the crack estimation area.
• the analysis area X which is estimated to cause stretch flange cracking in the intermediate part 10 corresponding to ⁇ , is obtained (see Fig. 12 ( ⁇ 0)).
• the pressed part 1 with the desired shape is formed at the end of the intermediate part 40 after shearing.
• the analysis area X at the end corresponding to ⁇ is heated at the above heating temperature and then cooled.
• the present embodiment also has the following effects.
• each of the first step 28 and the second step 2 may be composed of a plurality of press steps.
• the above heating/cooling treatment may be performed on the analysis area X corresponding to the end portion of the steel sheet 10 before the first step 2.
• the process of the above third embodiment is performed by regarding the press process in the middle other than the final press process as the first process. But it doesn't matter.
• the test material consisting of a steel plate was the target of the hole expanding test.
• the test material consists of a square blank material with a square shape of 100 x 100! As shown in Fig. 14, a hole with a diameter of 1 01 01 0 is opened in the center of the blank material. Then, a test piece 30 was prepared.
• the hole expansion ratio was calculated by removing the sample after the hole expansion test from the tester, measuring the hole diameter after the test with 4 calipers, and calculating the ratio of the average hole expansion !- and the initial hole diameter !_ 0 . ..
• Heating and cooling are performed by immersing a sample equipped with a thermocouple in a salt bath maintained at a specified temperature, heating the test piece 30 to the target temperature, and then air-cooling the test piece for hole expansion test 3 It was set to 0.
• Figure 16 shows the relationship between the heating temperature and the change in the hole expansion ratio.
• the vertical axis represents the rate of change of the hole expansion rate from the room expansion rate at room temperature (hole expansion property improvement rate).
• hole expansion property improvement rate the rate of change of the hole expansion rate from the room expansion rate at room temperature.
• this example shows an example in which the entire test piece 30 is heated and cooled, but when only the end portion (1 from the end face) of the hole opened in the test piece 30 is laser-heated and air-cooled. Even in this case, it has been confirmed that the improvement rate of hole expansibility is improved by setting the heating temperature in the temperature range of not less than 500 ° and not more than 700 ° .
• the main structure is steel sheet with martensite single phase. ⁇ 0 2020/175 486 38 ⁇ (: 170? 2020 /007513
• the steel plate 10 sheared as shown in Fig. 8(a) was press-formed into the target press part 11 shown in Fig. 8( ⁇ ) by the manufacturing method described below.
• the press part 1 the press part 1
• the estimated crack area 8 The analysis area X of the steel sheet 10 corresponding to ⁇ is determined, and after heating the analysis area X to a predetermined heating temperature and cooling it to room temperature, the steel sheet is formed into the part shape shown in Fig. 8 (13). Cold stamping was applied to the stamped part 1 1 of.
• Fig. 10 ( ⁇ ) A steel plate with a main structure of martensite single phase, which was sheared as shown in Fig. 10 (Slung) by the manufacturing method based on the process of the second embodiment, is shown in Fig. 10 ( ⁇ ).
• each of the heating conditions was 400 ° ⁇ , 600 ° ⁇ , and 800 ° ⁇ , and it was confirmed whether or not there was stretch flange cracking in the target press part 11.
• steel sheets shear-processed by the manufacturing method based on the treatment of the third embodiment are mainly used for martensite single-phase steel sheets.
• the intermediate part 40 is molded in the first step and a part of the end 403 of the intermediate part 40 is sheared, in the second step, the intermediate part 40 after shearing is processed into the desired press part shape.
• the main organization of tensile strength 1 1 80 IV! 3 grade is high-strength composed of martensite single-phase It was a steel plate.
• the predetermined heating temperature no heating, 400 ° ⁇ , 600 ° ⁇ , 800 ° ⁇ were carried out, and it was checked whether or not there was a stretch flange crack in the target press part shape.
• test piece of the hole expansion test is heated and air-cooled before the hole expansion.
• the test was conducted. The contents will be described below.
• the test material consisting of a steel plate was the target of the hole expanding test.
• the test material consists of a square blank material with a square shape of 100 x 100! As shown in Fig. 14, a hole with a diameter of 1 01 01 0 is opened in the center of the blank material. Then, a test piece 30 was prepared.
• Class 3 is mainly composed of a composite structure of martensite and ferrite. Strength steel plate.
• the manufactured test piece 30 was subjected to press working including stretch flange forming.
• a conical hole expansion test was performed using a conical punch to evaluate the stretch flange formability.
• a conical punch with an apex angle of 60 ° was used, and the test piece 30 was fixed with a lock bead 34 to prevent material inflow.
• reference numeral 32 indicates a die and reference numeral 33 indicates a blank material holder.
• Heating and cooling are performed by immersing a sample equipped with a thermocouple in a salt bath maintained at a specified temperature, heating the test piece 30 to the target temperature, and then air-cooling the test piece for hole expansion test 3 It was set to 0.
• Figure 17 shows the relationship between the heating temperature and the change in hole expansion ratio. ⁇ 0 2020/175 486 41 ⁇ (: 170? 2020 /007513
• FIG. 1 A first figure.
• the vertical axis represents the rate of change of the hole expansion rate from the room expansion rate at room temperature (hole expansion property improvement rate).
• hole expansion property improvement rate the rate of change of the hole expansion rate from the room expansion rate at room temperature.
• the heating temperature is at least 400 ° C, preferably at 500 ° C. From the above, it can be seen that the improvement of the hole expansion rate becomes large, and that the hole expansion rate remarkably decreases when heated up to 800°. From the above results, it was found that the stretch flange formability was reliably improved by heating in the temperature range of 400 ° C to 700 ° C.
• this example shows an example in which the entire test piece 30 is heated and cooled, but when only the end portion (1 from the end surface) of the hole opened in the test piece 30 is laser-heated and air-cooled. even, 4 0 0 ° ⁇ as 7 0 0 ° ⁇ following temperature region to be hole expansion improvement at the heating temperature has been confirmed that improved.
• a steel plate 10 sheared as shown in Fig. 8 (a) by the manufacturing method based on the treatment of the first embodiment using a steel plate having the first composite structure is used as the target shown in Fig. 8 (13). I tried press forming into a press part 1 1 with a press part shape.
• a steel sheet 10 sheared as shown in Fig. 10 (slung) by the manufacturing method based on the treatment of the second embodiment is changed from Fig. 10 ( ⁇ ) to Fig. 1 As shown in the order of 0 ( 6 ), we tried press forming through intermediate part 40 to press part 1 1 1 of the desired press part shape.
• the sheared steel sheet, 1 2 urchin by showing sequentially from (spoon) 1 2), molding the intermediate part 4 0 in the first step, the end portion 4 0 3 of the intermediate part 4 0 After shearing a part of the above, in the second step, the intermediate component 40 after the shearing treatment was press-molded into a press component 11 having a desired press component shape.
• the predetermined heating temperature without heating, 3 5 0 ° ⁇ , 6 0 0 ° ⁇ , it it performed at 8 0 0 ° ⁇ , tried to confirm the presence or absence of stretch flange crack in the press part geometry object.
• test piece of the hole expansion test is heated and air cooled, and then the hole expansion is performed.
• the test was conducted. The contents will be described below.
• the test material consisting of a steel plate was the target of the hole expanding test.
• the test material consists of a square blank material of 100 x 100 1 0 01 square, and as shown in Fig. 14, a hole with a diameter of 100 1 01 0 is opened in the center of the blank material, Test piece 30 was used.
• the produced test piece 30 was subjected to press working including stretch flange forming, and as shown in Fig. 15, a conical hole widening test was performed using a conical punch to evaluate the stretch flange formability. did.
• a conical hole expansion test a conical punch with an apex angle of 60 ° was used, and the test piece 30 was fixed with a lock bead 34 to prevent material inflow.
• reference numeral 32 indicates a die and reference numeral 33 indicates a blank material holder.
• Heating and cooling are performed by immersing a sample equipped with a thermocouple in a salt bath maintained at a specified temperature, heating the test piece 30 to the target temperature, and then air-cooling the test piece for hole expansion test 3 It was set to 0.
• Figure 18 shows the relationship between the heating temperature and the change in the hole expansion ratio.
• the vertical axis represents the rate of change of the hole expansion rate from the room expansion rate at room temperature (hole expansion property improvement rate).
• hole expansion property improvement rate the rate of change of the hole expansion rate from the room expansion rate at room temperature.
• the entire test piece 30 is heated and cooled.However, this is the case where only the end (1 from the end face) of the hole opened in the test piece 30 is laser-heated and air-cooled. However, it has been confirmed that the improvement rate of hole expansibility is improved by setting the heating temperature in the temperature range of 200 ° ⁇ to 700 ° ⁇ .
• a steel plate 10 sheared as shown in Fig. 8(a) by the manufacturing method based on the treatment of the first embodiment using a steel plate having a second composite structure was used as the target shown in Fig. 8(13). I tried press forming into a press part 1 1 with a press part shape.
• tensile strength was constructed high-strength steel sheet of a composite structure comprising a 1 1 80 IV! 3 grade residual austenite.
• the press part 1 As shown in Fig. 7, the press part 1 Then, as shown in Fig. 8(a), the estimated crack area 8
• the analysis area X of the steel sheet 10 corresponding to ⁇ was obtained, and after heating the analysis area X to a predetermined heating temperature and cooling to room temperature, the steel sheet was formed into the part shape shown in Fig. 8 (13). Cold stamping was applied to the stamped part 1 1 of.
• heating was performed under each condition of no heating, 180 ° ⁇ , 600 ° ⁇ , 800 ° ⁇ , and it was confirmed whether or not there was a stretch flange crack in the target press part 11.
• predetermined heating temperature conditions heating was not performed, and each of the conditions was 180 ° C., 600 ° C., and 800 ° C., and it was confirmed whether or not there was stretch flange cracking in the target press part 11.
• the steel plates sheared by the manufacturing method based on the treatment of the third embodiment using the steel plate having the second composite structure are After the intermediate part 40 is molded in the first step and a part of the end 40a of the intermediate part 40 is sheared, in the second step, the intermediate part 40 after the shearing is pressed into a desired press part shape. I tried to press-mold component 1 1.
• the crack estimation region RS K of the target shape press part 11 was obtained by CAE analysis based on the press forming conditions.
• the cold-pressed part 1 1 was cold-pressed.
• the predetermined heating temperature no heating, 180 ° ⁇ , 600 ° ⁇ , 800 ° ⁇ were carried out, and it was checked whether or not there was a stretch flange crack in the target press part shape.
• the test material consisting of a steel plate was the target of the hole expanding test.
• the test material consisted of a square blank of 10000 1000101 square. As shown in Fig. 14, a hole with a diameter of 1 001010 was opened in the center of the blank, and a test piece 30 was prepared. In this case, the hole was sheared with a punch of 11111110 and the circumference of the test piece after shearing with a punch of 9.81111110.
• the test was performed using two types of test pieces.
• the prepared test piece 30 was subjected to press working including stretch flange forming, and as shown in Fig. 15, a conical hole widening test was performed using a conical punch to evaluate the stretch flange formability. .. In the conical hole expansion test, a conical punch having an apex angle of 60 ° was used, and the test piece 30 was fixed with a lock bead 34 to prevent material inflow.
• reference numeral 32 indicates a die and reference numeral 33 indicates a blank material holder.
• the hole expansion ratio was calculated by removing the sample after the hole expansion test from the tester, measuring the hole diameter after the test with 4 calipers, and calculating the ratio of the average hole expansion !- and the initial hole diameter !_ 0 . ..
• test piece 30 For heating and cooling, immerse the sample equipped with a thermocouple in a salt bath maintained at a predetermined temperature, heat the test piece 30 to the target temperature, air-cool it, and prepare a test piece 30 for hole expansion test. did.
• Figure 19 shows the relationship between the heating temperature and the change in the hole expansion ratio.
• the vertical axis represents the rate of change of the hole expansion rate from the room expansion rate at room temperature (hole expansion property improvement rate).
• hole expansion property improvement rate the rate of change of the hole expansion rate from the room expansion rate at room temperature.
• the entire test piece 30 is heated and cooled.However, this is the case where only the end (1 from the end face) of the hole opened in the test piece 30 is laser-heated and air-cooled. However, it has been confirmed that the improvement rate of hole expansibility is improved by setting the heating temperature in the temperature range of 400 ° ⁇ to 700 ° ⁇ .
• a steel sheet with a main structure of bainite single-phase is manufactured by the manufacturing method based on the process of the first embodiment, and the steel sheet 10 sheared as shown in Fig. 8(a) is pressed into I tried to press-mold a part-shaped pressed part 1 1.
• the main structure was a high-strength steel sheet composed of bainite single phase.
• the press part 1 As shown in Fig. 7, the press part 1 Then, as shown in Fig. 8(a), the estimated crack area 8
• the analysis area X of the steel sheet 10 corresponding to ⁇ was obtained, and after heating the analysis area X to a predetermined heating temperature and cooling to room temperature, the steel sheet was formed into the part shape shown in Fig. 8 (13). Cold stamping was applied to the stamped part 1 1 of.
• the predetermined heating temperature conditions no heating, 350 ° ⁇ , 600 ° ⁇ , and 800 ° ⁇ were performed respectively, and it was confirmed whether or not there was a stretch flange crack in the target press part 11.
• a steel sheet with a main structure of bainite single-phase is manufactured by the manufacturing method based on the treatment of the second embodiment, and the steel sheet 10 sheared as shown in Fig. As shown in order from 0 (6), press molding was performed through the intermediate part 40 into the press part 11 having the desired press part shape.
• steel sheets shear-processed by the manufacturing method based on the treatment of the third embodiment in the main structure of bainite single-phase steel sheet are After the intermediate part 40 is molded in the first step and a part of the end 403 of the intermediate part 40 is sheared, in the second step, the intermediate part 40 after shearing is pressed into the desired press part shape.
• the press part 1 of the target shape was obtained by the 808 analysis based on the press forming conditions.
• the crack estimation area is shown in Fig. 12 ( ⁇ 0).
• the analysis area X of the intermediate part 40 after shearing corresponding to ⁇ is obtained.
• cold pressing was applied to the press part 11 of the part shape shown in Fig. 10 ( ⁇ ). ..
• the predetermined heating temperature no heating, 350 ° ⁇ , 600 ° ⁇ , 800 ° ⁇ were carried out, and it was checked whether or not there was a stretch flange crack in the target press part shape.
• the test material consisting of a steel plate was the target of the hole expanding test.
• the test material consists of a square blank material with a square shape of 100 x 100! As shown in Fig. 14, a hole with a diameter of 1 01 01 0 is opened in the center of the blank material. Then, a test piece 30 was prepared. In this case, the hole was sheared with a punch of 1 0 111 111 0 and the circumference was
• the test was performed using two types of test pieces.
• main tissue tensile strength 7 8 tertiary has to consist high strength steel sheets Fuwerai preparative single phase
• the produced test piece 30 was subjected to press working including stretch flange forming, and as shown in Fig. 15, a conical hole expanding test was performed using a conical punch to evaluate the stretch flange formability. did.
• a conical hole expansion test a conical punch with an apex angle of 60° was used, and the test piece 30 was fixed with a lock bead 34 to prevent material inflow.
• reference numeral 32 indicates a die and reference numeral 33 indicates a blank material holder.
• the hole expansion ratio was calculated by removing the sample after the hole expansion test from the tester, measuring the hole diameter after the test with 4 calipers, and calculating the ratio of the average hole expansion !- and the initial hole diameter !_ 0 . ..
• Heating and cooling are performed by immersing a sample equipped with a thermocouple in a salt bath maintained at a specified temperature, heating the test piece 30 to the target temperature, and then air-cooling the test piece for hole expansion test 3 It was set to 0.
• Figure 20 shows the relationship between the heating temperature and the change in hole expansion ratio.
• the vertical axis represents the rate of change of the hole expansion ratio from the hole expansion ratio at room temperature (hole expansion property ⁇ 02020/175486 52 ⁇ (: 170? 2020 /007513
• hole expandability improvement rate is shown.
• the hole expandability improvement rate is less than 100%, it indicates that the hole expandability is worse than in the unheated state.
• a hole expandability improvement rate of 100% or more indicates that the hole expandability is improved as compared with the non-heated state.
• the entire test piece 30 is heated and cooled.However, this is the case where only the end (1 from the end face) of the hole opened in the test piece 30 is laser-heated and air-cooled. However, it has been confirmed that the improvement rate of hole expansibility is improved by setting the heating temperature in the temperature range of 400 ° ⁇ to 700 ° ⁇ .
• the press part 1 As shown in Fig. 7, the press part 1 Then, as shown in Fig. 8(a), the estimated crack area 8
• the analysis area X of the steel sheet 10 corresponding to ⁇ was obtained, and after heating the analysis area X to a predetermined heating temperature and cooling to room temperature, the steel sheet was formed into the part shape shown in Fig. 8 (13). Cold stamping was applied to the stamped part 1 1 of.
• the predetermined heating temperature conditions no heating, 350 ° ⁇ , 600 ° ⁇ , and 800 ° ⁇ were performed respectively, and it was confirmed whether or not there was a stretch flange crack in the target press part 11.
• a steel sheet with a ferrite single-phase main structure which was shear-processed as shown in Fig. 10 ( ⁇ ) by the manufacturing method based on the treatment of the second embodiment, was manufactured from Fig. 10 ( ⁇ ) to Fig. 1 (O). As shown in order from 0 (6), press molding was performed through the intermediate part 40 into the press part 11 having the desired press part shape.
• the predetermined heating temperature conditions no heating, 350 ° ⁇ , 600 ° ⁇ , and 800 ° ⁇ were performed, respectively, and it was confirmed whether or not the stretched flange cracks in the target press part 11 were cracked.
• steel sheets shear-processed by the manufacturing method based on the treatment of the third embodiment, where the main structure is a ferrite single-phase steel sheet are After the intermediate part 40 is molded in the first step and a part of the end 403 of the intermediate part 40 is sheared, in the second step, the intermediate part 40 after shearing is pressed into the desired press part shape. I tried to press-mold component 1 1.
• a high-strength steel sheet whose main structure is composed of a single-phase ferrite.
• the predetermined heating temperature no heating, 350 ° ⁇ , 600 ° ⁇ , 800 ° ⁇ were carried out, and it was checked whether or not there was a stretch flange crack in the target press part shape.
• test piece of the hole expansion test is heated and air-cooled before the hole expansion.
• the test was conducted. The contents will be described below.
• the test material consisting of a steel plate was the target of the hole expanding test.
• the test material consisted of a square blank material with a size of 10000 1 000101, and as shown in Fig. 14, a hole with a diameter of 1 001010 was opened in the center of the blank material to obtain a test piece 30.
• the hole was sheared with a punch of 11111110, and the circumference was cut with a punch of 9.81111110.
• the test was performed using two types of test pieces.
• the prepared test piece 30 was subjected to press working including stretch flange forming, and as shown in Fig. 15, a conical hole widening test was performed using a conical punch to conduct elongation test. ⁇ 0 2020/175 486 55 ⁇ (: 170? 2020 /007513
• Heating and cooling are performed by immersing a sample equipped with a thermocouple in a salt bath maintained at a specified temperature, heating the test piece 30 to the target temperature, and then air-cooling the test piece for hole expansion test 3 It was set to 0.
• Figure 21 shows the relationship between the heating temperature and the change in the hole expansion ratio.
• the vertical axis represents the rate of change of the hole expansion rate from the room expansion rate at room temperature (hole expansion property improvement rate).
• hole expansion property improvement rate the rate of change of the hole expansion rate from the room expansion rate at room temperature.
• this example shows an example in which the entire test piece 30 is heated and cooled, but when only the end portion (1 from the end face) of the hole opened in the test piece 30 is laser-heated and air-cooled. even, 4 0 0 ° ⁇ as 7 0 0 ° ⁇ following temperature region to be hole expansion improvement at the heating temperature has been confirmed that improved. ⁇ 02020/175486 56 ⁇ (: 170? 2020 /007513
• the steel plate 10 shear-processed as shown in Fig. 8(a) by the manufacturing method based on the treatment of the first embodiment is shown in Fig. 8(13) as the target press part shape. It was tried to press-mold into the pressed part 11 of.
• the press part 1 As shown in Fig. 7, the press part 1 Then, as shown in Fig. 8(a), the estimated crack area 8
• the analysis area X of the steel sheet 10 corresponding to ⁇ was obtained, and after heating the analysis area X to a predetermined heating temperature and cooling to room temperature, the steel sheet was formed into the part shape shown in Fig. 8 (13). Cold stamping was applied to the stamped part 1 1 of.
• the predetermined heating temperature conditions no heating, 350 ° ⁇ , 600 ° ⁇ , and 800 ° ⁇ were performed respectively, and it was confirmed whether or not there was a stretch flange crack in the target press part 11.
• the steel sheet 10 sheared as shown in Fig. 10 (slung) by the manufacturing method based on the treatment of the second embodiment is changed from Fig. 10 ( ⁇ ) to Fig. 10
• press molding was carried out through the intermediate part 40 to obtain the desired press part shape press part 11.
• the predetermined heating temperature conditions no heating, 350 ° ⁇ , 600 ° ⁇ , and 800 ° ⁇ were performed respectively, and it was confirmed whether or not there was a stretch flange crack in the target press part 11.
• the steel sheet shear-processed by the manufacturing method based on the treatment of the third embodiment is shown in FIG. 12 (13) to FIG. 12 ( ⁇ ) in order.
• the intermediate part 40 is formed in the process and a part of the end part 40 3 of the intermediate part 40 is sheared, in the second process, the intermediate part 40 after the shearing process is pressed into the desired pressed part shape. I tried press molding to 1 1.
• the stamped part 1 of the target shape was obtained by the Ohami analysis based on the conditions of the press molding.
• the crack estimation area is shown in Fig. 12 ( ⁇ 0).
• the analysis area X of the intermediate part 40 after shearing corresponding to ⁇ is obtained.
• cold pressing was applied to the press part 11 of the part shape shown in Fig. 10 ( ⁇ ). ..
• the predetermined heating temperature no heating, 350 ° ⁇ , 600 ° ⁇ , 800 ° ⁇ were carried out, and it was checked whether or not there was a stretch flange crack in the target press part shape.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Child & Adolescent Psychology (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Punching Or Piercing (AREA)
• Heat Treatment Of Articles (AREA)

Priority Applications (6)

Applications Claiming Priority (12)

Publications (1)

Family

ID=72239948

Family Applications (1)

Country Status (7)

Citations (13)

Family Cites Families (10)

• 2020
  • 2020-02-25 US US17/433,921 patent/US20220049324A1/en active Pending
  • 2020-02-25 MX MX2021010285A patent/MX2021010285A/es unknown
  • 2020-02-25 KR KR1020217026801A patent/KR102612142B1/ko active IP Right Grant
  • 2020-02-25 JP JP2021502279A patent/JP7276428B2/ja active Active
  • 2020-02-25 EP EP20763410.6A patent/EP3932579A4/en active Pending
  • 2020-02-25 WO PCT/JP2020/007513 patent/WO2020175486A1/ja unknown
  • 2020-02-25 CN CN202080016401.XA patent/CN113474100B/zh active Active

Patent Citations (13)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events